Device for renewing air in a confined enclosure

ABSTRACT

Device (10, 110) for renewing air in an enclosure, including a discharge means (14) for the air inside the enclosure containing harmful vapors and/or polluted air and/or humidity, a fan (22) being located within the discharge means and being suitable to convey this inside air through the discharge means, and a means (26) for opening the door of the enclosure that makes it possible to lock and unlock the door, the unlocking of the door being subsequent to a manual or automatic opening command from an opening control means, the door remaining locked when the opening means is activated, its deactivation being performed after unlocking conditions are met. The device additionally includes at least a means (17, 27) for purifying the air before it is evacuated through the exhaust duct.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to devices and methods used for the renewal of vapours and/or polluted air contained in a closed confined space such as a refrigerator intended to contain products releasing such vapours and/or polluted air, or a dishwasher intended for cleaning the containers for these products, and in particular, relates to a device for renewing air in a confined enclosure.

BACKGROUND ART

In a laboratory, products that must be kept at temperatures below room temperature are stored in refrigerators. Some of these products present various dangers such as fire, explosion and health risks. They can sometimes release substances that are harmful to users who repeatedly inhale them each time the refrigerator is opened.

It should be remembered that, according to the National Institute for Research and Security (INRS), a chemical laboratory in which operations are carried out with products emitting vapours or gases, and the refrigerators in this laboratory, must be equipped with a ventilation system able to capture these vapours or gases in order to maintain a permanently healthy indoor atmosphere.

Furthermore, at the end of a series of manipulations carried out in the laboratory, the equipment used is washed in dishwashers. At the end of the washing cycle, when the doer is opened, a large quantity of hot steam exits the machine, which is a disadvantage for the operator, ail the more so if the room contains several dishwashers located side by side and which operate at the same time. Steam increases the humidity level in the room and requires that the operator wait until the dishes cool down before removing them from the machine. In addition, the operator is subjected to the release of hot steam which may contain harmful substances that come from the washed glassware.

Many documents describe ventilation devices used for closed enclosures to prevent toxic fumes from being breathed in. Thus, patent EP 2816306 describes a ventilation system for the treatment of agricultural and gardening products inside a closed storage room, comprising an air mixing unit equipped with a fresh air inlet, an air circulation inlet, a mixing lid which, depending on its extent of opening, mixes fresh air with circulation air inside the mixing unit, and a fan arranged to distribute air in the room.

Patent WO 9706390 relates to a combined unit allowing air renewal and its conditioning in a controlled atmosphere space and comprising an air discharge chamber, an air recycling chamber, an air supply chamber and a fresh air chamber. A supply fan is used to draw air out of the air supply chamber and an exhaust fan is used to draw air out of the air discharge chamber.

Patent FR 2633376 describes a device made up of one or more individual storage modules comprising a refrigerator accessible through a door, separated in the height direction by slatted shelves and an air distribution grid. The device comprises a suction duct and a ventilation duct opening into the heat-insulated enclosure, above the air distribution grid. The renewal air is drawn from the ambient air and air renewal is carried out using a fan according to a program determined according to the nature and quantity of the products grouped by affinity in the shelves.

Document WO 2015/032905 describes a method for preventing leakage of a hazardous gas from a container such as the leakage of flammable refrigerant gas in a storage space and describes a container comprising leak protection provided with a means for blocking the access door to this container.

Permanent air renewal/ as is the case in documents EP 2816306 and WO 9706390, requires that the refrigerator work continuously to maintain the set temperature. As the compressor is forced to run almost permanently—an operation for which it was not designed—its service life is considerably reduced. In addition, the associated energy consumption is exceedingly high. In the case of document FR 2633376, the air renewal is intermittent but depends on a predetermined program unrelated to the opening of the refrigerator door by an operator.

SUMMARY OF THE INVENTION

This is why the main object of the invention is to provide a device for renewing air in a confined enclosure, the operation of which precedes the opening of the door by an operator and stops when the door is closed. The main object of the invention is thus a device for renewing air in an enclosure comprising a means for discharging the air inside the enclosure containing harmful vapours and/or polluted air and/or humidity, a fan being located within the discharge means and being suitable to convey this inside air through the discharge means, a means for opening the door of the enclosure that makes it possible to lock and unlock the door, the unlocking of the door being subsequent to a manual or automatic opening command thanks to an opening control means, the door remaining locked when the opening means is activated, its deactivation being performed after unlocking conditions are met. The device additionally comprises at least a means for purifying the air before it is discharged through the exhaust duct.

BRIEF DESCRIPTION OF THE DRAWINGS

Other purposes, objects and characteristics of the invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic representation of the air renewal device according to the invention,

FIG. 2 is a block diagram of the air renewal device according to the invention,

FIG. 3 is a schematic representation of the air renewal device according to a second embodiment,

FIG. 4 is a block diagram of the air renewal device specific to the second embodiment of the invention,

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 3, the air renewal device 10 or 110 according to the invention is integrated into an enclosure 12, for example by being fixed to the door of the enclosure or on one of its walls. The air contained in the enclosure contains harmful vapours and/or pollutants and/or moisture and is referred to as “charged air” in the following description.

The air renewal device 10 or 110 comprises an exhaust duct 14 requiring that a hole be made in the wall of the enclosure 12 for discharging the charged air contained inside the enclosure.

The exhaust duct 14 has an opening damper 16 which allows the charged air to be discharged from the enclosure when the duct is open as shown by the arrows 13 and 20. A ventilation means, such as a fan 22, is started after the damper 16 is opened, causing the charged air to be discharged from the enclosure. The air renewal device also includes a means for purifying the discharged air, that is to say, to make it healthier. This means can be a means for retaining harmful particles such as a filter 17 placed upstream of the fan 22. The charged air extracted from the enclosure thus passes through the filter 17 before being discharged in the exhaust duct 14. The air discharged in the exhaust duct is purified so as to avoid the release of polluting particles into the atmosphere.

When the room in which the enclosure 12 is located has a centralized ventilation means, the latter can foe used to ventilate the enclosure by connecting the exhaust duct to this ventilation means. In addition, when the charged air is directly discharged into the room where the enclosure is located, the means for purifying the charged air before discharging it makes it possible to prevent the personnel passing through the room from being exposed to harmful particles and/or the humidity of the air discharged from the enclosure.

It is to be noted that, as the charged air is extracted and discharged from the enclosure, outside air, as shown by arrow 36, enters the enclosure through an air inlet duct 30 fixed to one of the walls of the enclosure that is pierced beforehand so as to renew the air inside the enclosure. The air inlet duct includes a check valve 32 and a filter 34.

The air renewal device 10 includes a panel of three indicators. An indicator 23 (white) lights up when the device 10 is powered, an indicator 24 (red) lights up if the device has a problem. The third indicator 25 (green) is a push button that flashes as long as the door of the enclosure is locked and lights up continuously when the door is unlocked. It is to be noted that the indicators could be replaced by other equivalent means performing the same functions.

Finally, the air renewal device 10 includes a means 26 for opening the enclosure door, making it possible to lock and unlock the door. The door opening means 26 can be an electromagnet which prevents the door of the enclosure from opening as long as it is activated. As soon as it is no longer activated and that, consequently, the indicator 25 remains permanently on, the enclosure door is unlocked and can therefore be opened. It is to be noted that the electromagnet could have an emergency deactivation means such as a push button.

The fan 22 continues to extract the air through the duct 14 after the enclosure door has beer, opened detected by a door opening contact) and does not stop until the door is subsequently closed. It is to be noted that the damper 16, which operates in parallel with the fan, also remains open until the door closes. Thus, the fan is stopped when the door is closed. This characteristic is important insofar as the enclosure is at a slight negative pressure, which makes it possible to protect the operator in the event that the inside air has not yet been completely renewed and still presents a danger. Therefore, the fan must continue to run until the door is closed.

With reference to FIG. 2, the air renewal device according to the invention comprises a PLC 28 suitable to control the various means used.

When the PLC 26 receives the order to unlock the door, it sends a command to the damper 16 to open exhaust duct 14. Almost simultaneously, the PLC 28 sends an activation command to the fan 22. Then, the PLC 28 sends a command to the electromagnet 26 to deactivate it in order to open the door of the enclosure when certain unlocking conditions are met.

The air inlet duct 30 comprises an automatic opening and flow regulation means such as a damper controlled by the PLCs 28 and 128. This opening means could also be an automatic valve with a small orifice allowing limited air entry.

SPECIFIC FEATURES OF THE REFRIGERATOR

The enclosure 12 can be a refrigerator containing chemicals which must be kept at a temperature below ambient temperature. These products belong to categories of products presenting a health hazard. In particular, they can give off harmful vapours and/or pollutants which can prove to be dangerous or even toxic for an operator who has to handle them.

In the case of a refrigerator, the command to control the unlocking of the door is, in most cases, manual and initiated 5 by actuation of the opening control means. The opening control means includes the push button or indicator light 25 but may also include another means such as an infrared detection sensor activated by a hand entering its field of vision. So, when an operator wishes to open the refrigerator, he/she presses the push button to command the opening. This command is received by the PLC 28 which then performs the steps previously described. The device according to the invention, can include a presence detector, and the command to unlock the door can also be initiated by the detection of the presence of 5 an operator by this detector. The opening control means “button” and “infrared sensor” as well as “button” and “presence detector” can be combined.

The unlocking conditions for a refrigerator are, for the most part, pre-established, that is to say, they are configured in advance according to the nature of the products that the refrigerator must contain, their concentration and the volume of air to be extracted. As will be seen below, certain conditions, known as security conditions, can also be added in an exceptional manner to the conditions needed for unlocking the door of the enclosure 12.

The PLC 28 can also automatically initiate the unlocking of the door and therefore the start of the air renewal cycle after a predetermined period of time has elapsed during which no command to open the door has been initiated. This delay is useful for discharging pollutants which can concentrate in the refrigerator when the air contained therein has not beer, renewed for an extended period such as overnight or over the weekend.

SPECIFIC FEATURES OF THE DISHWASHER

The enclosure 12 can be a dishwasher used in chemical laboratories to clean glassware. With reference to FIG. 3, inside the enclosure 12, therefore inside the dishwasher, a water protection cover 35 is placed over the hole made in the wall, which opens into the exhaust duct 14 to prevent water from entering the latter. In addition, a check valve 33, located at the beginning of the exhaust duct 14, prevents charged air from re-entering the enclosure 12 in the direction opposite the arrow 20.

In the case of a dishwasher, the inside air is mainly charged with hot, humid steam and may also contain harmful residual particles from the washed glassware. The air renewal device 110 also comprises a means for purifying the discharged air, that is to say, to make it healthier. This means can be a means 27 for reducing the humidity level of the discharged air such as a steam trap associated with a retention tank 29, which collects the condensates. The steam trap is located in the exhaust duct 14 just downstream the check valve 33. The steam trap is, for example, a device for separating droplets by inertia composed of a set of blades of sinusoidal shape. The flow of discharged humid air passes between the blades while the water droplets, due to their greater inertia, cannot follow the changes of direction and collide with the blades. The droplets are trapped and gather to form a liquid which is drained by gravity to a retention tank 29. The retention tank is emptied manually or can be connected to the draining system of the dishwasher.

Before being discharged in the exhaust duct 14, the air can also pass through a particle filter such as the filter 17.

Referring to FIG. 4, the air renewal device according to the embodiment applied to the dishwasher, comprises a PLC 128 suitable to control the various means used.

The door unlocking command can be received by the PLC 128 in two different ways. The command can be manual by actuation of the push button or indicator light 25 by the operator, and the command can be automatic following the reception of a washing cycle end signal 37 from the electronic card 39 of the dishwasher. This function requires that the PLC 128 of the air renewal device 110 be electronically connected to the electronic card of the dishwasher. Manual actuation of the door unlocking control allows the operator to open the door even though the wash cycle is not complete. In both cases of manual or automatic opening control/ when the PLC 128 receives the order to unlock the door, it sends a command to the damper 16 to open the exhaust duct 14. Almost simultaneously, the PLC 128 sends an activation command to the fan 22. Then, the PLC 128 sends a command to the electromagnet 26 to deactivate it in order to open the door of the enclosure when certain unlocking conditions are met.

As long as the fan is running, the PLC receives data measured by sensors 31 about temperature, humidity level, and the amount of harmful particles in the charged air coming from inside the dishwasher. Preferably, the sensors are placed in the exhaust duct 14 between the means 27 for reducing the humidity level of the discharged air and the opening damper 16, but could also be located upstream of the means 27. When each piece of measured data reaches a certain threshold programmed and stored in the PLC, the unlocking conditions are met, arid the dishwasher door can be opened.

When the retention tank is connected to the draining system of the dishwasher, it can be emptied automatically at the end of the ventilation cycle by a solenoid valve not shown) controlled by the PLC 128.

The device according to the invention applied to the dishwasher makes it possible to avoid operators being exposed to hot steam when the door is opened but also makes it possible to protect the air exhaust ducts against mould due to excessive humidity.

SAFE OPENING CONDITIONS

The red indicator lights up if a problem occurs, i.e. when the safety conditions for the operator and the facility are no longer met. The red indicator 24 can also be coupled to an audible alarm such as a buzzer.

When the charged air is discharged from the enclosure 12, the inside pressure is lower than the outside pressure. Indeed, a vacuum is required inside the enclosure to prevent the charged air from exiting through the door when it is opened. It is, therefore, a good idea to install a vacuum sensor, the measurement of which is added to the conditions necessary for the enclosure door to unlock. If the vacuum is below the threshold value programmed and recorded in the PLC 28 or 128, the red indicator 24 lights up, and the buzzer beeps to warn the user about a ventilation malfunction and the electromagnet, remains activated.

In the case of a refrigerator, when an operator actuates the opening control means too often, the temperature of the refrigerator may increase and may become higher than a predefined limit temperature. As with the vacuum detector, it is a good idea to install a temperature sensor inside the refrigerator, the measurement of which is added to the conditions necessary for the enclosure door to unlock. For example, a temperature sensor measures the temperature in a control bottle containing glycol water placed in the refrigerator. If the temperature is above the threshold temperature programmed and recorded in the PLC 2S, the red indicator flashes, the buzzer beeps, the electromagnet remains activated, and the ventilation is cut off.

However, when the red indicator lights up, if the operator still wants to open the enclosure door, he/she must make a long press on the push button 25, for example for at least 3 seconds. Similarly, if the operator wishes to open the door in an emergency without triggering the operation of the enclosure air renewal device, a door opening system can be provided, for example by pressing and holding the button or the green indicator 25. 

1. A device (10, 110) for renewing air in a confined enclosure (12) comprising a means (14) for discharging the air inside the enclosure containing harmful vapours and/or polluted air and/or humidity, a fan (22) being located within said discharge means and being suitable to convey this inside air through said discharge means (14), and a means (26) for opening a door of said enclosure that makes it possible to lock and unlock the door, the unlocking of the door being subsequent to a manual or automatic opening command thanks to an opening control means, the door remaining locked as long as said opening means is activated, its deactivation being performed after unlocking conditions are met; and at least one means (17, 27) for purifying the air before it is discharged through said exhaust duct.
 2. The device according to claim 1, wherein said fan continues to operate after the enclosure door has been opened and does not stop until the door is subsequently closed.
 3. The device according to claim 1, wherein said exhaust means (14) includes a damper (16) which, when open, allows the air inside the enclosure to exit the enclosure.
 4. The device according to claim 3, comprising a PLC (28, 128) for controlling the opening of said damper (16) and the start-up of said fan, as well as the opening of the door of said enclosure by said opening control means.
 5. The device according to claim 4, wherein said opening means is an electromagnet (26), the deactivation of which, controlled by said PLC, causes the refrigerator door to unlock.
 6. The device according to claim 4, wherein an air inlet duct (30) is fixed to one of the walls of the enclosure so as to renew the air inside the enclosure as the polluted air and/or harmful vapours are discharged and comprises a damper, the opening of which is controlled by said PLC (28).
 7. The device according to claim 1, wherein the means for purifying the air discharged from said enclosure (12) is a means (17) for retaining harmful particles from the discharged air.
 8. The device according to claim 1, wherein the means for purifying the air discharged from said enclosure (12) is a means (27) for reducing the humidity level of the discharged air.
 9. The device according to claim 8, wherein said means (27) for reducing the humidity level of the discharged air is a device for separating droplets by inertia, composed of a set of sinusoidal blades in which the water droplets are trapped due to their greater inertia and gather to form a liquid drained by gravity to a retention tank (29).
 10. The device according claim 1, wherein a vacuum detector inside the enclosure provides a measure which is added to the conditions necessary for the door of the enclosure to unlock.
 11. The device according to claim 4, wherein said opening control is manual and is associated with said opening control means mainly comprising a push button (25), the depression of which by an operator causes a signal to be sent to said PLC (28, 128) which causes said PLC to command the opening of the door, said push button being an indicator which flashes as long as the door is not unlocked and which remains permanently illuminated as soon as the door is unlocked.
 12. The device according to claim 4, wherein said enclosure (12) is a refrigerator comprising a temperature sensor which provides a measurement of the temperature inside said enclosure which adds to the conditions necessary for the door of said enclosure to unlock.
 13. The device according to claim 12, wherein said opening control means also comprises an infrared detection cell or a presence detector.
 14. The device according to claim 12, wherein said opening command is automatic after a predetermined time has elapsed during which no door opening command has been initiated.
 15. The device according to claim 4, wherein said enclosure (12) is a dishwasher and wherein said air renewal device (110) is electronically connected to the electronic card (39) of said dishwasher.
 16. The device according to claim 15, wherein said automatic opening command is subsequent to the reception of a washing cycle end signal (37) originating from said electronic card (39) of said dishwasher.
 17. The device according to claim 15, wherein said unlocking conditions depend on data measured by sensors (31) for temperature, humidity level and the amount of harmful particles in the charged air coming from inside the dishwasher, said unlocking conditions being reached when each piece of said measured data reaches a certain threshold programmed and recorded in said PLC (128) .
 18. The device according to claim 15, wherein said recovery tank (29) is connected to the draining system of the dishwasher.
 19. The device according to claim 18, wherein the emptying of said recovery tank (29) is automatically carried out at the end of the ventilation cycle by a solenoid valve controlled by said PLC (128). 